1. Field of the Invention
This invention relates, in general, to water heating devices, and, more particularly, to solid fuel heaters for outdoor tanks, hot tubs, and the like.
2. Description of the Prior Art
Because electricity and because natural gas and other conventional fuels are many times inaccessible and because of the efficiency in burning wood, coal, pellets, and other solid fuels, it is highly desirable to provide an immersible solid fuel burning heater for heating water in hot tubs, tanks, and other containers.
A number of such water heaters are in existence. The first of such heaters, as typified by U.S. Pat. No. 881,362, issued to A. W. Van Rinsum; U.S. Pat. No. 966,147, issued to E. B. Wills; U.S. Pat. No. 1,268,202, issued to M. E. Anderson; and U.S. Pat. No. 1,468,561, issued to H. A. Friend, were much in the nature of a conventional wood stove having a sealed housing for immersion into a tank. In such heaters, the fuel is loaded directly into the combustion chamber where it is ignited and burned. Such heaters were provided with top opening lids for loading the fuel and for closure during combustion. Similar, were simplified versions in which a single tube served as a fuel reception tube; an air intake tube; and a combustion chamber, as shown by U.S. Pat. No. 1,061,147, issued to Trachte and U.S. Pat. No. 1,329,035, issued to W. S. Bryson. Such versions were plagued by the problems of pulling the heated fumes downwardly, in a direction contrary to natural upward flow of heated gases, and in further pulling the heated gases through the fuel and burned ash. In overcoming these problems, an air conduit, separate from the fuel tube, was provided in heaters invented by S. Anderson and L. Hanson, U.S. Pat. No. 1,187,227 and by D. A. Tisdale, U.S. Pat. No. 1,056,684.